[tialaramex]

The first transistors are 1947. We don't use that sort of transistor today, but unlike the vacuum tube it would have been obvious that a computer built from these transistors was viable. You can't get to the iPhone from there, but room size machines that do arbitrary Turing computation are only expensive. So that means it's in the realm of supersonic flight. If you must do it you can, but maybe you'll decide it's too expensive.

By 1950 then, the only question is whether we should, not whether we can.